Multiblade grab

ABSTRACT

A grapple adapted to be suspended to a hoisting means such as a crane-hook or a wire-block, the said grapple comprises a housing open at the bottom and is provided with a plurality of radially and star-shaped grab blades and an electromagnetically operated valve and a drive mechanism for operating the blades. The drive mechanism consists of an electric motor coupled to a pump arranged to produce operating pressure in a hydraulic cylinder and thus to operate a piston to which is attached a crosshead, each of the grab blades being pivotally attached at one end to the crosshead, and each blade being pivotally mounted on an axle at an intermediate point to an intermediate link each intermediate link being pivotally attached to the housing, so that up-and-down movements of the crosshead closes and opens the grab blades. An inner collar bearing is mounted around the axle, each end of the said collar bearing abutting against sideplates located on each side of the grab blades. The collar is adapted to keep the said sideplates safely spaced from the blade under even very powerful stresses.

[72] lnventor Sven E. Hansen 4300 Osterled, 20, Holbaek, Denmark [21] App]. No. 875,367 [22] Filed Nov. 10, 1969 [45] Patented Nov. 23, 1971 [32] Priority Oct. 9, 1969 [33] Denmark [31] 5,366/69 [54] MULTIBLADE GRAB 4 Claims, 5 Drawing Figs.

[52] U.S.Cl 294/106 [51] Int. Cl B66c 3/04 [50] Field of Search 294/106,

107,108,109,11OR,111,112,116 [56] References Cited UNITED STATES PATENTS 1,935,898 11/1933 Zimmerman et al 294/106 X 2,757,038 7/1956 Drill 294/110 X 2,832,629 4/1958 Anderson 294/110 X 2,862,756 12/1958 Larson 294/106 X 3,527,495 9/1970 Maradyn 294/106 X Primary E.raminer-Joseph Wegbreit Almrney Raymond A. Robic ABSTRACT: A grapple adapted to be suspended to a hoisting means such as a crane-hook or a wire-block, the said grapple comprises a housing open at the bottom and is provided with a plurality of radially and star-shaped grab blades and an electromagnetically operated valve and a drive mechanism for operating the blades. The drive mechanism consists of an electric motor coupled to a pump arranged to produce operating pressure in a hydraulic cylinder and thus to operate a piston to which is attached a crosshead, each of the grab blades being pivotally attached at one end to the crosshead. and each blade being pivotally mounted on an axle at an intermediate point to an intermediate link each intermediate link being pivotally attached to the housing, so that up-and-down movements of the crosshead closes and opens the grab blades. An inner collar bearing is mounted around the axle, each end of the said collar bearing abutting against sideplates located on each side of the grab blades. The collar is adapted to keep the said sideplates safely spaced from the blade under even very powerful stresses.

PATENTEDNUV 23 |97l SHEET 1 BF 2 nvvawrae Sven HANSEN ATTORNEY PATENTEDuuv 23 Ian 3, 622. l 92 sum 2 0F 2 MULTIBLADE GRAB The present invention relates to a grapple adapted to be suspended to a hoisting means such as a crane-hook or a wireblock. The grapple comprises in combination a housing opened at the bottom, a plurality of radially and preferably star-shaped, arranged grab blades, an electromagnetically operated valve, a drive mechanism for operating the blades, the drive mechanism comprising an electric motor coupled to a pump arranged to produce operating pressure in a hydraulic cylinder with a piston and a piston rod attached to a crosshead, to which the inner ends of the individual arms of the grab blades are hinged, which grab blades are moreover individually hinged to a bearing block by means of a first axle pivotally mounted in this block, which block is pivotally mounted on a second axle at right angles to the first axle and located between prongs of a connecting linkage, the upper end of said linkage is hinged to the said housing by means of a third axle parallel to the first axle. The housing encloses the valve, the motor, the pump, the hydraulic cylinder and at least part of the piston, a connecting rod of the connecting linkage and the bearing block is provided with surfaces arranged to abut against each other to limit the relative lateral movement in both directions without thereby subjecting the pivotal connections to unfavorable stresses, the bearing block being provided with a prismatic groove and the connecting rod being provided with a corresponding prismatic ridge, the said ridge and the said groove both extending coaxially on the axis of the pivotal connection between the connecting rod and the bearingblock, the faces of the said ridge and groove being arranged so that after a specified degree of lateral movement in either direction, one face of the ridge becomes parallel to and abuts against a corresponding face of the said groove to inhibit further lateral movement, an inner collar bearing around the first axle in the said block, each end of the said collar bearing abutting against sideplates located on each side of the block of the grab blades, the said collar adapted to keep the said sideplates safely spaced from the block under even very powerful stresses. The bearing collar around the first axle comprises two bearings, the outer extreme ends of the said two bearings abut against the said sideplates. Between the inner ends of the said two bearings, hard smooth washers are located. These washers are preferably made of tempered smoothly polished steel. The two bearings around the first axles comprise spherical ball joint bearings.

FIG. 1 shows at a small scale a grab according to the invention, in side view and partly in vertical section;

FIG. 2 shows a connection link of same on a larger scale and likewise in side view and partly in vertical section;

FIG. 3 shows the same connection link, viewed partly in section on the line Ill-III in FIG. 2;

FIG. 4 shows a lower part of this connection link, likewise viewed partly in section on the line III-III in FIG. 2, but with parts of it in another position; and

FIG. 5 shows a lowest part of this connection link, likewise viewed partly in section on the line IIIIII in FIG. 2, but on still larger scale.

Numeral 1 is a tapered tubular housing provided with a cover 2 attached thereto, with centrally and symmetrically located lugs with ears for a schackle 4 for attachment on a crane-hook 5 or directly on a wire-block. Centrally under the cover 2 is rotatably suspended a hydraulic cylinder 6 with a not-shown piston and piston rod 7 hinged to a crosshead 8 with lugs 9, to which are hinged the inner and upper ends 10 of arms of grab blades 11 which are by means of connection links 12 connected to axles 13 in bearings 14 under a ring 15 at the bottom of the tubular housing 1.

To each axle 13 an end of a rod 16 of a connecting link 12 is fastened by welding. The rod 116 is at the other end elaborated as a fork with prongs 17 and 18 with holes to receive ends of an axle 19, which is held undisplaceable between the prongs 17 and 18 by means of a locking plate 20, which is fastened to the prong l7 and reaches below into a recess on the axle 19. Around same and in a hole 22 in a block 23 spherical ball joint bearings 21 are located the outer collars 24 of which are by means of lockrings 25, seeger-rings, kept undisplaceably tight in the hole 22, and the extreme ends of the inner collars 26 of which are facing each prong 17 or 18 of its own.

At right angles to and under the hole 22 there is in the block another hole 27 with spherical ball joint bearings 28 round an axle 29 in the hole 27. Each of the ends of the axle 29 is located fastened in a hole in a sideplate 30 or 31 of a gripper or grab blade 11. To the sideplate 30 is fastened a locking plate 32, reaching below into a recess in the axle 29. The extreme end of an inner collar 33 of one of the ball joint bearings 28 is facing the inner sides of each of the sideplates 30 and 31 tightly. The inner ends of the inner collars are each facing a guide washer 34 round the axle 29. Between the latter and a guide ring 35 in the hole 27 a thrust bearing ring or washer 36 is located, inside same another thrust bearing washer 37, inside each of these a spacing washer 38 and between these two a lock or seeger ring 39, reaching a little outside the hole 27 and into the surrounding material of the block 23. The washers 34, 35, 36, 37 and 38 are tempered and smoothly polished steel washers, between which the friction is so small, that the axle 29 with the grab blade 11 may rotate freely with so little clearance that the sideplates 30 and 31 of the grab blade are always held with the shown spacing from the block 23. In the axle 19 there is a groove 40 for the injection of lubricant or ball bearing grease into the mutually connected holes 22 and 27 and into the ball joint bearings in these holes.

In the block 23 a prismatic-shaped key groove 41 with side surfaces 42 is elaborated, which surfaces are surrounding side surfaces 43 of a prism 44 stationarily located between the prongs 17 and 18. The angles between the surfaces 42 and 43 are so, that a surface 42 is facing a surface 43 when the block 23 is rotated about the axle 19 to the position shown in FIG. 2 in full or dotted lines, in which position the surfaces 42 and 43 are forming a powerful stop for a limited lateral movement of the block 23 and consequently of the grab blade 11 when same closes round a not-shown burden. The extreme collars of the bearings 28 are marked 45.

What is claimed is:

l. A grapple the said grapple comprising a housing open at the bottom, a plurality of radially arranged grab blades, an electromagnetically operated valve, a drive mechanism for operating the blades, the drive mechanism comprising an electric motor coupled to a pump arranged to produce operating pressure in a hydraulic cylinder and thus to operate a piston with a piston rod attached to a crosshead, the inner ends of individual arms of the grab blades are hinged to said crosshead, on intermediate portion of said grab blades are individually hinged to a bearing block by means of a first axle pivotably mounted in the said block, the said block is pivotably mounted on a second axle at right angles to the first axle and located between prongs of a connecting linkage, the upper end of said linkage is hinged to the said housing by means of a third axle parallel to the first axle, the housing enclosing the valve, the motor, the pump and the hydraulic cylinder, and at least part of the piston, a connecting rod of the connecting linkage and the bearing block being provided with surfaces arranged to abut against each other to limit the relative lateral movement in both directions without thereby subjecting the pivotal connections to unfavorable stresses, the bearing block being provided with a prismatic groove and the connecting rod being provided with a corresponding prismatic ridge, the ridge and groove both extending coaxially of the axis of the pivotal connection between the connecting rod and the bearing block, their faces being arranged so that after a specified degree of lateral movement in either direction, one face of the ridge becomes parallel to and abut against a corresponding face of the groove to inhibit further lateral movement, an inner collar bearing around the first axle in the said block, each end of the said collar bearing abutting against sideplates located on each side of the block of the grab blades, the said collar adapted to keep the said sideplates safely spaced from the block under even very powerful stresses.

washer is made of tempered polished steel.

4. A grapple in accordance with claim 2, wherein the two bearings around the first axles c 5 bearings.

omprise spherical ball joint 

1. A grapple the said grapple comprising a housing open at the bottom, a plurality of radially arranged grab blades, an electromagnetically operated valve, a drive mechanism for operating the blades, the drive mechanism comprising an electric motor coupled to a pump arranged to produce operating pressure in a hydraulic cylinder and thus to operate a piston with a piston rod attached to a crosshead, the inner ends of individual arms of the grab blades are hinged to said crosshead, on intermediate portion of said grab blades are individually hinged to a bearing block by means of a first axle pivotably mounted in the said block, the said block is pivotably mounted on a second axle at right angles to the first axle and located between prongs of a connecting linkage, the upper end of said linkage is hinged to the said housing by means of a third axle parallel to the first axle, the housing enclosing the valve, the motor, the pump and the hydraulic cylinder, and at least part of the piston, a connecting rod of the connecting linkage and the bearing block being provided with surfaces arranged to abut against each other to limit the relative lateral movement in both directions without thereby subjecting the pivotal connections to unfavorable stresses, the bearing block being provided with a prismatic groove and the connecting rod being provided with a corresponding prismatic ridge, the ridge and groove both extending coaxially of the axis of the pivotal connection between the connecting rod and the bearing block, their faces being arranged so that after a specified degree of lateral movement in either direction, one face of the ridge becomes parallel to and abut against a corresponding face of the groove to inhibit further lateral movement, an inner collar bearing around the first axle in the said block, each end of the said collar bearing abutting against sideplates located on each side of the block of the grab blades, the said collar adapted to keep the said sideplates safely spaced from the block under even very powerful stresses.
 2. A grapple in accordance with claim 1 wherein the bearing collar around the first axle comprises two bearings, the outer extreme ends of the said two bearings abutting against the said sideplates, and a hard smooth washer located between the inner ends of the said two bearings.
 3. A grapple in accordance with claim 2, wherein the hard washer is made of tempered polished steel.
 4. A grapple in accordance with claim 2, wherein the two bearings around the first axles comprise spherical ball joint bearings. 